


the perfect slave

by WattStalf



Series: Commissions [206]
Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: F/F, F/M, Foot Jobs, Leashes, Multi, Objectification, Sibling Incest, Slavery, Spanking, Spit Kink, Watersports, commission
Language: English
Status: Completed
Published: 2020-10-06
Updated: 2020-10-06
Packaged: 2021-03-08 02:20:48
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, Underage
Chapters: 1
Words: 6,012
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26858113
Author URL: https://archiveofourown.org/users/WattStalf/pseuds/WattStalf
Summary: Spinoff from the perfect pet.Slavery is perfectly legal in Brigid, but Byleth has chosen this lifestyle for herself. When Petra's younger brother has an important birthday, she lets him use Byleth as a gift.
Relationships: My Unit | Byleth/Original Character(s), Petra Macneary/My Unit | Byleth
Series: Commissions [206]
Series URL: https://archiveofourown.org/series/1325462
Kudos: 7





	the perfect slave

Byleth and Petra have been together for a while now.

It starts when they hardly know each other, when Byleth is still a professor at the academy Petra is studying at, as a “guest” of the Empire. They barely interact with one another until one day, during a routine mission to clear out bandits, Petra swoops in to save Byleth when she believes the professor is in over her head. From that point on, the two of them begin to bond quite a bit, until Petra is ready to take Byleth to Brigid with her, to show her how relationships work there, and what kind of relationship she would like to have with her.

Byleth is quickly enamored with the lifestyle, and she agrees to return with Petra permanently once Petra’s time at the academy is over. And so, when that day comes, she resigns as a professor to follow her former student, a princess soon to be queen, back to her homeland, where she will spend the rest of her days serving her as a one hundred percent legal slave.

The first thing that the two of them do once Byleth is home with her is have her marked as Petra’s property. She is given a tattoo of a dagger right on her ass, a symbol that shows she belongs to Petra, so that everyone will know it. Since she will be exposed most of the time, it will just take one glance at her to show who she belongs to, and if she is ever separated from the royal family, they will know where to return her to. It is a sign of ownership and a sign that she is no longer herself, reduced only to a piece of Petra’s property.

From that day on, her days are filled with happiness, serving Petra’s every need, and Petra could not be more pleased to have her beloved here with her.

~X~

Byleth has many uses while serving Petra, including serving anyone that Petra decides to share her with. That is why, when her younger brother has a very important birthday approaching, Petra decides that Byleth will be the perfect gift for him. He is still a bit younger than she was when she first met Byleth, but older enough to be curious about these things, and old enough to be allowed to have his fun with one of the royal slaves. Naturally, Byleth has no say in this, but if she did, she would likely be eager for her new work.

Petra’s brother is certainly eager for it, and he has had his eye on his sister’s slave for quite some time now. It is hard not to notice a slave as gorgeous and as obedient as Byleth, and since he has not been old enough to properly use a slave before, all he has been able to do is watch from afar, eager for the day that he will be able to claim a slave of his own. Of course, he knows that no one would ever compete with Byleth, so Petra knows that the best gift imaginable would be giving him a day with her slave.

He is finally old enough, and soon he will be choosing one of his own. Why not let him have a little bit of fun with his ideal slave for a little while, so that he can learn the ropes? It will serve as a gift and as a learning experience all at once, and he will get a lot out of it, she is sure. She explains to Byleth everything that she expects of her, and Byleth is eager to give her all for it.

When the day finally comes, Byleth is prepared to be given to him by being tied up with her arms behind her back, and her ankles bound to her wrists, laying face down with a blindfold and a gag. She is not worried about this vulnerable position because she trusts her mistress, and knows that this is part of the plan to give her little brother a very memorable birthday. Once she is bound up, Petra tops it all off with a bow, so that it will be clear that this is meant as a present.

Byleth is left alone, tied up like this while she waits for Petra and her brother to show up. Once they finally do, she hears the door swing open, as Petra cries out, “Happy birthday!” to her brother, speaking in their language. In addition to learning to serve Petra, Byleth has spent a lot of her time in Brigid learning the language, so that she can properly communicate with everyone she meets, and can understands direct orders without making Petra speak in the language of Fodlan. She has all but left her old life behind.

“Is this what I think it is?” she hears Petra’s brother cry out in surprise.

“You get to play with her as much as you want, just for today,” Petra replies. “I can’t give her to you forever, but you can at least have some fun with her to celebrate your birthday. You’ll want to learn how to handle slaves before you get your first slave, won’t you?”

“Oh, thank you so much! This is the best gift ever!” he cries. “Can I unwrap it now?”

“Of course, and do whatever you want to do with her,” she replies, and Byleth can hear them getting closer. The first thing he does is take off the blindfold, so that she can see him, and then he removes the gag.

“I’m going to untie you, so we can go for a walk,” he says. “How does that sound?”

“Your wish is my command,” Byleth replies. “And by the way, happy birthday. I hope you have a lot of fun using me for the day.” He looks like he could not be happier right now, and she is glad to be able to bring him so much joy.

“I want to take you out on a walk!” he declares, saying it more like an order this time, and not asking how she feels about it. He has seen the way slaves are treated, so he knows that those sorts of questions do not matter, because they have to go along with it either way. It just must be difficult for him to get used to things, when it is finally his turn to be able to do something like that. Either way, Byleth has no doubts that he will pick up on it by the time his birthday is over, with Petra as an example. Not to mention the fact that Byleth herself has been considered quite a good teacher in the past.

He gets her untied so that she can crawl on all fours, and secures a collar around her neck with a leash. It is far from the first time Byleth has been paraded around like this, but it will be his first time taking anyone for a walk, and he knows that he will get plenty of attention when he goes out walking his sister’s beloved slave everywhere, showing her off as if she is his own. Petra agrees to wait here for him, where she promises that she will have even more fun in store for him once he has finished doing what he wants to do.

With that, he starts off, yanking the leash hard to let Byleth know that he is ready to go, and she is left to follow along behind him. She has become a pretty popular sight when walking in public, seeing as she is not only the famed slave of the princess, but also that she is clearly from Fodlan. Remarks are often made about her paleness, something that Petra says she finds beautiful about her. Of course, the kindness of the remarks varies greatly based on who is saying it, but Byleth does not mind, just as long as she knows that her mistress loves it and loves her, and that she is always good enough for Petra.

Her little brother seems to enjoy leading her around, completely naked with her tattooed ass on display. If there were any doubt of who she was before, the dagger mark would clue anyone in, and seeing her with the young prince helps to confirm that as well. It is a well-known fact that today is his birthday, so he is greeted cheerfully everywhere he goes. A few comments are made here and there about his pale little pet that he is taking for a walk, and he has a laugh about that, joining in with the others who tease Byleth for her appearance, as well as her low status. Even the lowest of peasants greatly outrank here, where she is seen as nothing more than an animal, or maybe even an object.

But to her, none of that matters, because she is here with Petra, to make Petra happy. Serving the one that she loves is much more important to her now, and she has adjusted to these values and this culture, and she is perhaps the most willing slave in all of Brigid. Being mocked is a part of the job, and a part that she gladly accepts, even getting a bit of a thrill out of now. Now that she has spent so much time living like this, she has developed an even bigger submissive side than she had before, and so she does not mind that submission rules every aspect of her day to day life.

Coming upon a puddle in the road, he stops short and yanks on her leash. “You aren’t going to make a royal prince walk through that puddle, are you?” he asks her. “Not to mention the fact that it’s my birthday! You had better get down there and make a bridge for me, so I don’t have to walk through it.” They both know that he could walk around it, that there is plenty of space in either direction, but he has chosen to cut right through it, specifically because he knows that he can use Byleth for something like this. He has seen it done so many times before, and knows that is the benefit of having a living object to serve you; it becomes an inconvenience to simply walk around a puddle, when you have something to lay across it and let you pass.

Byleth has done this for Petra many times before, so she is quick to act, laying down to stretch her body across the puddle and offer him a proper path, where he does not have to get dirty to cross over. She can feel the water and mud all over her skin, but as long as it does not touch her temporary master, everything is just fine.

Soon enough, she feels his feet digging into the backs of her legs, pushing her further into the puddle, making an even bigger mess out of her. Byleth keeps her mouth and eyes closed so that she does not swallow any of it or blink it in, and he takes his time walking over her, stepping hard as he goes, just to make sure that she is really trampled down. She feels him step along her lower back, and then her upper back, and then one foot on the back of her head, and as it steps off, another foot on the back of her head.

Finally, he has made his crossing, and he yanks her leash hard, commanding her to get up so that they can keep going. She struggles to stand and he does not seem to notice or care, and he ignores the state she is in now, a complete mess soaked in muddy water. He still wants to keep going on his walk, of course, so she just has to follow along, getting back on her hands and knees to crawl behind him while he tugs her leash.

Everyone can see just how filthy Byleth is as she makes her way through the streets like this, and her temporary master seems to really love showing that fact off. Anyone who saw her would know that she has made a mess of herself just because of him, all to show her devotion. Everyone knows that Byleth is incredibly dedicated, willing to do anything for the one that she serves, and even if today is dedicated to the younger brother of her mistress, she is no less dedicated than ever before, and she is still doing just as much to make sure that the day goes perfectly.

Even though she keeps up a good pace with him, he will sometimes speed up just so that he can yank her leash harder, dragging her along with him and hurting her a bit in the process. Being rough is not always necessary, but that seems to be a part that he really likes, and she certainly does not mind that roughness, more than eager to keep up with him and to let him drag her whenever he is not satisfied with how fast she is going. He runs whatever made up errands that he has, just to have an excuse to walk her around as much as possible, and leave her tied up outside whenever he needs to go in anywhere.

Often, she will be tied up alongside other slaves, where she will still stand out, being from Fodlan and all. Slaves from other continents and nations are considered rare and oftentimes very valuable, but it does not change the fact that they stand out and seem unusual. And, due to the poor relations between Brigid and Adrestia in the past, most people tend to look down on any slaves with an appearance that suggests that they could be from Fodlan. Their pale skin and features are often jeered at, which is why Petra’s little brother has so much fun teasing Byleth about how pale she is. Byleth, of course, takes it all in stride, but also finds herself getting a bit of a thrill from it, finding that her submissive streak extends so far as to get her excited when she is being mocked for something like where she is from.

Petra does not do it very often, but she does occasionally, because she knows that Byleth likes it. Most of the time, that is how things work between them, with it feeling rather different than some of the relationships that Byleth sees when she looks around her. But, then again, she supposes that not everyone treats it like a relationship. She is just fortunate that she and Petra fell for one another, and that both were comfortable and happy with living out their relationship like this, in a way that conforms to Petra’s culture without raising too many brows about their relationship. Everything has been perfect for her since she moved here.

“Come on, let’s get going,” he says, coming back outside to untie her leash so that he can keep walking her. “We won’t be out for much longer, Petra says she wants to do more to celebrate my birthday and to teach me how to use you when we get home, so I want to get back.”

“That sounds exciting,” she replies. “I look forward to seeing how she teaches you to use me.”

“I bet I already know all her tricks! I’m gonna blow her away with how good I am at using a useless, pale slave like you,” he teases her. She has no idea if he really knows what he is doing well enough to keep up that kind of image or not, but either way, she is excited to see what happens when the time finally comes, eager to spend time with him and with Petra no matter what that will entail.

“But first, there is something I need to take care of before we go back home,” he continues, stopping in the road, and she looks up at him. They are right in the middle of a crowd, and she wonders what errands he still needs to do, when he has already done so much.

“Do we need to buy something?” she asks, not able to see if there are any shops for the crowd around them. However, he only laughs, and shakes his head.

“Not like that, it’s something we can do right here in the middle of the street. Open your mouth, and keep it open,” he commands her, and of course Byleth has no trouble following an order like that. She opens her mouth wide, looking up at him, and as he gets his pants undone, she realizes what he needs to take care of. He was not talking about an errand at all, but rather, something a lot more fun for him, something that he could easily wait until he got home to take care of, but of course he wants to do it right here and now, in the middle of this crowded street. He wants there to be an audience for this, and wants to publicly humiliate Byleth by using her to relieve himself, pissing right into her mouth.

And Byleth is more than willing to go along with that, keeping her mouth wide open as he aims and lets loose. At first, his aim is not stellar, probably on purpose, so that he can soak her face with his piss, but then, he manages to focus entirely on her mouth, letting her catch it all, swallowing and gulping it down, drinking it until his bladder is finally empty. Only then is he ready to head back home, yanking hard on her leash to lead her along.

Byleth is very excited to see what lies in store for her once they have reunited with Petra and can continue with his birthday celebrations, with her at the center of everything.

~X~

When he returns home, Petra is eager for them to get started with everything. She is excited to be able to properly share her slave and lover with her brother, eager to teach him as many things as possible, and to see what all he already knows about this sort of thing. By the time Byleth and her brother return, he is excited as well, with the first thing that he wants to do in mind.

“You’ll spoil me too, won’t you, Petra?” he asks her, and with a face like that, she can’t exactly say no to him, not on his birthday. So she agrees, and he says what he wants first, with all of them getting into the position to do it, after both he and Petra have stripped down. Byleth is made to get behind him, so that she can kiss his ass, showing her respect and her willingness to follow orders and her willingness to degrade herself, all at once. He teases her with, “Wow, you got there fast. It’s almost like you just want to do it, not like you’re a slave following orders!” They all know that her devotion goes much deeper than that, but he still makes the quip anyway.

Byleth does not reply because she is too busy peppering his rear with kisses, so devoted and so affectionate that he could never doubt how serious she is about this. While she does that, Petra gets ready for her part in this, which will be using her feet to please him. There are many times that she has caught him looking at her feet when they were bare and he thought she would not notice, so it is no surprise to her that, when given the chance to be spoiled by her, this is the first thing that he asks for.

Byleth would be much better at something like this, but Petra is more than happy to give it a try for his sake, just to help make his birthday memorable. She loves her brother so much, more than enough to spoil him in whatever way that he might ask for, so using her feet to get him off sounds like a great way to show that to him. She sits back so that she can put the soles of her feet on either side of his cock, already achingly hard in his growing excitement.

She gently squeezes his cock between her feet, making sure to put on just enough pressure that he will feel good, but not so much that she hurts him. He moans out happily, so she knows that she is doing this just right, and slowly, she starts to move them up and down, stroking his cock like she would with her hands. This, however, is a lot less controlled, so she has to be careful that her movements do not become too clumsy, and that she continues to make him feel absolutely amazing, better than he has ever felt before. The way he moans urges her on, making her want to keep going until she is able to get him off.

“That’s good, that’s very good,” he says with a content sigh, talking to both of them. He feels like the royalty he is when he is being spoiled not only by the most desirable slave he has ever met, but also by Petra, who is not only his older sister, but also will greatly outrank him someday, since she is the heir to the throne and will be queen, ruling over everyone in no time at all. Having her use her body for his pleasure certainly brings its own thrills to the table.

“You’re both doing such a good job, I could get used to living like this,” he says playfully, as the pleasure courses through his body. It is rare that he gets the chance to feel this good, though he has a feeling it will become more often, once he is able to claim a slave of his own. That will be any day now, but he is not sure if anyone will ever be able to top the pleasure that he gets from Petra and from Byleth. The two of them show him just how much fun he can be having, and show him just what the ideal connection between master and slave is. At the very least, he knows that he is going to be incredibly picky about everything.

For now, though, everything is perfect, and he has nothing else to worry about, not a care in the world. Petra strokes him off with her feet, getting him closer and closer, while Byleth still peppers his ass with kisses, degrading herself while worshiping him, just like he wants it, and just like he loves it. She is truly an expert at this sort of thing, probably picking up on it all so quickly because of how willing she was to sign herself up for this kind of lifestyle, whereas most slaves have to be broken in and taught how to behave. Byleth wanted to learn from the start, because she wanted to be the perfect match for Petra, and now, she seems to be the absolute ideal, even if some will look down on her because they can tell, at a glance, that she is from Fodlan. That sort of thing does not bother her.

The closer he is driven to his climax, the louder his moans become, arching his back and whining out for his sister, who continues to work her feet up and down, picking up the pace as she realizes that he is nearly there. There is no way that he can hold out for much longer, and she loves to see him whine and squirm like this, pushed closer and closer to the edge, losing his train of thought until he is not able to speak anymore, offering no more praise for them, his moans serving as more than enough praise.

He is pushed closer and closer until he can’t take it anymore, until the pleasure becomes far too much for him to bear, and he is overwhelmed by sensation and emotion, by all of the feelings that have threatened to overpower him all along, and there is nothing he can do to feet off his climax. Between his sister and her slave, there is nothing he can do, other than give into it entirely, the bliss crashing over him all at once as he finally lets himself let go, coming hard with a long and low moan of utter indulgence.

When he comes, he erupts right then and there, getting his seed all over his sister’s feet, and she remains in place, keeping her feet still so that he is able to cover them with his come as he moans and shudders, riding out the waves of his pleasure. Petra watches him with a bit of pride, glad that she was able to bring him to such a point all on her own, and to make him feel this good as a result of her treatment. She knows that her beloved brother will never forget this milestone birthday of his.

“Look at that mess I made,” he says, gazing at her feet and feeling rather proud of himself. Of course, he already knew that he would end up coming on her feet and making a mess of her, just as soon as he knew that he was going to get a footjob from her. So he already knows what he is going to do next, or rather what he is going to make Byleth do next, while he gets to sit back and enjoy the show. He has been waiting for this, waiting for the moment when he came, so that he could enjoy this.

“Stop what you’re doing right now,” he commands Byleth, and without wasting a second, her barrage of kisses comes to a stop. “You have a new job now. I have made quite the mess out of my sister’s feet, so I need you to clean up after me. Right away.” He is a little brisk with her orders, wanting to enjoy the feeling of power over her, and Byleth is quick to move so that she can get to work, following his directions and pleasing him with her swiftness, as she kneels before her usual mistress.

Byleth is very used to licking Petra’s feet, though this will be the first time that she has ever licked come off of them. That makes it all the more exciting to her, and she starts off slowly, dragging her tongue along, getting a taste for it, pleased to find that she likes the taste quite a bit. She decides to take her time so that she can savor it, licking slowly along one foot, making sure to get every last bit of it cleaned up, and even then, she lingers for quite a while, still wanting to lick as much as she possibly can, in case she left anything behind.

After that, she follows the exact same path along the other foot, glad to be able to savor the taste all over again, ecstatic with the way that it lingers in the back of her mouth as she continues to lick along Petra’s foot. Once again, she is as thorough as she can possibly be, and by the time that she is done, both feet are completely spotless, with no evidence of the mess remaining. Even so, she wants to spend a little bit more time worshiping at Petra’s feet, so she decides to do a little bit more to her.

First, she licks along the soles of her feet again, still taking her time, as reverent as she can possibly be, desperate to show all of her love to her mistress. Once she is satisfied with that, she then sucks each toe, one by one, working her way along Petra’s feet and taking that as slowly as she can, making sure to spend equal time sucking each toe, so that she knows that she is giving Petra the attention that she deserves. And once each toe on each foot has been thoroughly sucked, she sucks five at once, spending the same amount of time on each foot, rolling her tongue around as she goes.

Finally, she pulls back and says, “Thank you so much for letting me lick your feet clean.”

“You did an excellent job cleaning me,” Petra replies, and Byleth is once again struck by how regal her voice sounds when she is speaking her native language, nowhere near as clumsy as she sounded back when she was still one of Byleth’s students. Truly, she is worthy of being queen, and Byleth is lucky to be able to serve her so directly.

Her attention turns to her brother suddenly, her voice becoming detached as she says, “You did a pretty good job with it so far, but I want to teach you more ways that you can use it.” There is always a thrill involved in hearing Petra refer to her as ‘it’, treating her as little more than an object. As much as she knows that Petra truly loves her, there is a lot of excitement in being talked about as if she is nothing, as if she is just a toy to be used, whenever they want to use her.

“I made it do so much for me already,” he replies. “What else can it even do?” He asks the question teasingly, because he knows full well that Byleth is capable of a lot more than what they have done today. He has seen her with Petra so many times that he knows quite a lot about what she is capable of, and he asks this dismissive question specifically to try and degrade her a little, as if he does not quite believe that she serves any other purposes than what he has already seen.

“How about you try punishing it? You can do anything you want to it, and even punish it when it has not done anything wrong. You seem like the type who would enjoy something like that, so why not give it a try?” she suggests. And it is true that he seems to have a sadistic streak, much bigger than she does, so the idea of being able to punish Byleth despite Byleth behaving as the perfect slave all day certainly seems like an appealing idea to him.

Grinning, he orders Byleth down onto her knees, and circles around her for a moment, looking as if he is contemplating what he wants to do to her. Of course, it does not take him very long to reach a decision, and soon enough, he has come around behind her, raising his arm up so that he can bring his hand down square on her ass, spanking her with a resounding smack. She lets out a yelp at the sudden sting; even though she is used to much worse pain than that, the first smack always takes her by surprise, even if she is fully prepared for it.

And once he hears her cry out like that, he is only further encouraged to keep striking her, just like he wants to, as hard as he possibly can, getting harder when he has the chance, but also having to rest and take it easy from time to time, because he lets himself put too much force behind it at once and wear himself out. That is when he has to rest a bit, giving her light smacks, but that is almost worse, because it means that she gets used to be spanked with light force, and is always taken by surprise the moment that he picks up the pace again.

All the while, Petra watches him and does not scold or tease him for needing to slow down at times. She must see that it serves as a good tactic, whether it is done intentionally or not. And so, she is able to focus more on encouraging his use of her slave, until she decides to start doing some things for herself. While he is behind Byleth, spanking her quite brutally, Petra remains in front of her, giving her full access to the other woman’s face, perfect for what she has in mind.

She spits on her face, aiming straight for Byleth’s cheek, and as soon as her slave feels the moisture hitting her face, as soon as she realizes what it is, she begins moaning in between her cries of pain, excited to have Petra spitting on her and degrading her even more. It is all so good to her, and she tries her best to keep her mouth open, so that when Petra spits at her, it will sometimes land in her mouth. Petra is good at aiming, so when Byleth tries to catch it, she usually does, unless she is trying to spit somewhere else on her face, like in her eyes or the center of her forehead, doing her best to degrade her while her brother continues to spank her, turning her ass raw and red with each smack of his hand.

She is completely helpless, and by the time that they are done with her, she slumps forward, out of her mind with all of the thoughts and sensations swirling around in her. They have one last thing that they want to do to her, to finish off her day serving Petra’s little brother. He seems very excited as he goes to get some things, and Petra tells Byleth that she needs to lay back and be very still while they do that.

“Sure thing, but what are you doing?” she asks, curious.

Petra simply smiles and says, “You’ll see.”

When her brother return, though, it is very evident what they are going to be doing. With the fabrics that he has brought, they start to wrap Byleth up, while she keeps her limbs pressed tight to her body. She is not allowed to move during this whole process, but she knows for certain that, by the time they are done with her, she will not be able to move at all, wrapped up tight like some kind of mummy. She holds still just like she promised she would, doing just as Petra tells her, like she always does. She is obedient in all things, and if this is the last thing that her master’s brother wants to do on his birthday, then this is something that she will have to do perfectly, so that he will always have fond memories of this day, and of his time bossing around Byleth for a little while.

The tighter it gets, the more wrapped up she is, the more restricted she feels. Now, she is not just staying still by choice; there is no way that she would be able to move. And once they have tightly wrapped and encased her body in the tight fabric, they move on to her face, and then everything goes dark. She can’t see either of them, and the tighter that they wrap her, the more that they add, the more she wonders if she will even be able to breathe during all of this. Breathing will certainly become difficult, and the pose is uncomfortable, and she has no way of knowing just how long she will have to be wrapped up like this.

That idea just makes it all the more exciting for her.

Their voices are muffled when they are finally done wrapping her up, but she can here them talking about how Petra’s little brother will be using her as a pillow now that she is wrapped up like this. That will be his final gift for his birthday, getting Byleth to be his living pillow, and she will not be able to move the entire time that he lays on her. As always, she is a perfectly obedient slave.

**Author's Note:**

> If you're interested in my writing updates, please follow my fanfiction twitter @WattStalf  
> 


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